This invention relates to the determination of geoligical orientations, and more particularly, to a method of determining and displaying these preferred orientations.
In geophysical exploration, for example, the mapping of subsurface formations is important. Plots depicting the depth, dip and azimuth (i.e., azimuth of the dip) of subsurface formations are important geophysical tools. Many different types of measurements are made to provide the raw data from which the depth, dip and azimuth of the subsurface formations are determined. Seismic exploration, well logging and gravimetric measurements, for example, have been used to provide data regarding the depth, dip and azimuth of subsurface formations. Usually, these measurements do not consistently represent the true dip and azimuth of the formations. For this reason, it is common to apply a smoothing or averaging procedure to the raw measurements in order to determine the preferred orientation of the subsurface formations. See Structural Geology, M. P. Billings, Prentice Hall, 3rd Ed. 1972, p. 377, for a discussion of the manner of determining and depicting the preferred orientation of subsurface formations.
Structural geologists, petrologists, sedimentologists and others use three-dimensional orientation analysis in their studies of the depositional environments. Examples of the gathering of measurements which supply three-dimensional data regarding the earth's subsurface include U.S. Pat. No. 4,241,429--Bloomquist et al wherein seismic measurements are made in a manner which can be used to determine the three-dimensional orientation of the subsurface layering of the earth. Another extensively used measuring technique includes the use of a dipmeter logging tool. Dipmeter logging is described in "The High Resolution Dipmeter Tool", Log Analyst, Vol. 10, No. 3 (May-June, 1969), pp. 3-11, Allaud, L. A., and Ringot, J; "Automatic Computation of Dipmeter Logs Digitally Recorded on Magnetic Tapes", JPT (July, 1962), pp. 771-782, Moran J. H., Coufleau, M. A., Miller, G. K., and Timmons, J. P.; "The Continuous Dipmeter as a Tool for Studies of Directional Sedimentation and Directional Tectonics", SPWLA 9th Annual Logging Symposium (June 23-26, 1968), pp. G1-25, Rodriquez, A. R., and Pirson, S. J.; and "A Three Dimensional Vector Method as an Aid to Continuous Dipmeter Interpretation", Geologie En Mijnbouw, Vol. 50, No. 6 (1971), pp. 725-732.
It is an object of the present invention to determine and depict the preferred orientations in depositional environments and in other orientation studies as represented by dipmeter, petrofabric and other geological and geophysical measurements.